1. Field of the Invention
The present invention relates to a sensor, and more particularly, to a biosensor device.
2. Description of Related Art
Biosensors are expected for measurements in biological features such as corpuscles, proteins, carbohydrates, antibodies or metal ions. Biosensors are advantageous for their high specificity, high sensitivity and high selectivity, and are applicable in the fields of medicine, biological technology, food, agriculture and environment monitoring.
There are several types of biosensors, for example, electrochemical biosensor, semiconductor ion sensor, fiber-optic biosensor and piezoelectric quartz crystal biosensor. FIG. 1 shows a prior sensor device 1. In the fabrication of the prior sensor device 1, a silicon oxide (SiO2) layer 12 is disposed on a poly layer 11. A bulk 13 covers the SiO2 layer 12 and the poly layer 11. The bulk 13 and the SiO2 layer 12 are etched to form a well 14. The poly layer 11 is used as a sensing element. However, in the manufacture of the prior sensor device 1, the bulk 13 needs to be etched for a large depth which is difficult to control, and there should be another process for etching the SiO2 layer 12. Moreover, since the etching of the SiO2 layer 12 is inconsistent with the standard CMOS fabrication, it is difficult to control the remaining thickness of the SiO2 layer 12, and as a result, the yield factor of the prior sensor device 1 varies.
Therefore, it is desirable to provide an improved biosensor to mitigate or obviate the aforementioned problems.